Method for establishing a foundation in particular for a tower of a wind energy plant

ABSTRACT

The invention relates to a method for building a foundation for a structure comprising a plurality of segments, in particular for a wind turbine tower, a foundation segment for use in such method, and a wind turbine. In order to create a stable foundation, a method comprising the following steps is proposed on the basis of experience gained:_excavating a foundation bed,_building a stable, substantially level and horizontal subbase in a foundation bed, setting down a foundation segment of the structure on the subbase, wherein at least three vertically adjustable support poles are fixedly attached to said foundation segment by means of a supporting bracket mounted at the end of the support poles in such a way that only the support poles are placed onto predetermined points of support on the subbase,_producing a reinforcement on the subbase,_filling the remainder of the foundation bed with foundation mass, in particular concrete, to a level above the bottom rim of the foundation segment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method for building a foundation for astructure comprising a plurality of segments, in particular for a windturbine tower. The invention also relates to a support pole, afoundation segment for such a structure and a wind turbine.

2. Description of the Related Art

Constructing a permanently stable and level foundation is of enormousimportance for larger structures. Particularly in the case of a windturbine tower, which can be more than 100 m in height and be exposed inoperation to enormous forces, the foundation must conform to exactingspecifications.

Wind turbine foundations are currently constructed by firstly making aso-called subbase in a foundation bed, in other words a cement orconcrete base layer that is as level and horizontal as possible. Supportpoles for setting down the foundation segment on the subbase are thenmounted on the foundation segment, i.e., the lowermost segment of atower comprised of several segments. In order to compensate for anyunevenness in the subbase and to align the foundation segment ashorizontally as possible, the support poles can be screwed varyingdepths into the underside of the foundation segment, the support polesbeing configured for this purpose as threaded poles in at least theupper section facing the underside of the foundation segment.

There have been cases in which support poles have either penetrated intothe subbase or broken off from the underside of the foundation segmentas a result of the enormous lateral loads exerted on the support polesby the foundation segment, which can currently weigh between 10 and 14metric tonnes. This has resulted in the foundation segment overturning.In addition to the dangers to which persons engaged in constructing thefoundation were exposed, this has led not only to delays but also toadditional costs for remedying the damage caused.

BRIEF SUMMARY OF THE INVENTION

One object of the invention is therefore to provide a method forbuilding a foundation for a structure comprising a plurality ofsegments, in particular, for a wind turbine tower; an improved supportpole; a suitable foundation segment and a wind turbine in which theaforementioned problems are avoided.

This object is accomplished pursuant to the invention by a methodaccording to claim 1, said method comprising the following steps:

-   -   a) excavating a foundation bed,    -   b) building a stable, substantially level and horizontal subbase        in a foundation bed,    -   c) setting down a foundation segment of the structure onto the        subbase, wherein at least three vertically adjustable support        poles are fixedly attached to said foundation segment by means        of a supporting bracket mounted at the end of the support poles        in such a way that only the support poles are placed onto        predetermined points of support on the subbase,    -   d) producing a reinforcement on the subbase,    -   e) filling the remainder of the foundation bed with foundation        mass, in particular concrete, to a level above the bottom rim of        the foundation segment.

The invention is based on the realization that the problems occurringwith methods to date can be avoided if the support poles are not screweddirectly into the underside of the foundation segment, but instead arefixedly attached to distributed points on the foundation segment bymeans of supporting brackets, e.g., in the form of a support plate,before the foundation segment is set down on the subbase. The verticaladjustment means are still provided on the support poles, but elsewherethan hitherto, and the height of the segment is adjusted by screwing thesupport poles by different amounts into the underside of the foundationsegment. The supporting brackets provide the foundation segment with asignificantly larger supporting surface on the support poles, and hencea significantly improved distribution of load. This means that bucklingof a threaded pole at the underside of the foundation segment will nolonger occur.

In order to prevent the support pole from penetrating the subbase, theinvention also provides for reinforcement of those points where thesupport poles bearing the foundation segment are set down on thesubbase. These points may be reinforced over a larger area by installing(additional) reinforcement mats and/or by providing local reinforcement,for example by making the subbase higher at predefined positions. Analternative or additional means is to use base plates. These can be laidat predefined positions on the subbase so that the support poles can beset down on them, or they are mounted on the support pole at theopposite end from the supporting bracket.

After the foundation segment with the support poles has been set down onthese points of support or base plates and been vertically adjusted tocompensate for differences in height, the rest of the foundation bed isfilled with foundation mass, for example with concrete, in one or morefilling steps, the foundation mass being poured in until it reaches alevel that is above the lower rim of the foundation segment, thusachieving a stable foundation. Owing to this stable support for thefoundation segment, problems that are known to occur during this finalcasting process when prior art methods are used, particularly changes inthe position of the foundation segment when it is being filled withfoundation mass, no longer occur.

In one preferred configuration, the support poles are each attached bymeans of support plates to a flange mounted on the underside of thefoundation. The support plates are preferably bolted to the flange. Thisenables particularly good positioning and support of the foundationsegment on the support poles to be achieved.

In an alternative configuration, the support poles are each attached toa flange around the upper rim of the foundation segment. To this end, itis preferred that the supporting bracket at the upper end of the supportpole be configured in such a way that it can be firmly attached to theflange, for example by bolting together the flange and the bracket. Toensure that the foundation segment is securely supported, it is alsopreferred in such a configuration that the support poles pass througheyes attached to the lower rim of the foundation segment and extendinside the foundation segment.

In the final step of the method, the foundation bed can be filled withfoundation mass in a single casting. In a preferred version,particularly when the support poles are configured as just described,the rest of the foundation bed can also be filled in two steps. In afirst step, the foundation bed is filled with foundation mass to a levelapproximately equal to that of the lower rim of the foundation segment.Any vertical alignment of the foundation segment that is necessary canthen be carried out in order to compensate for any shifts in theposition of the foundation segment during the first casting step, and aposition achieved that is as horizontal as possible. To this end, thesupport poles have the vertical adjustment means in a section that ofcourse has not yet been filled with foundation mass at this time.Finally, once the foundation segment has been vertically aligned, therest of the foundation bed can then be filled until the desired level offoundation mass is reached.

In another configuration according to the invention, the rest of thefoundation bed is filled with foundation mass to such a height thatholes provided in the side walls of the foundation segment are covered,the foundation mass being poured into the hollow interior of thefoundation segment as well.

In a preferred embodiment, a row of holes is provided around thecircumference of the foundation segment and equidistant from theunderside of the foundation segment. Reinforcement wires are braidedthrough said holes to form a mechanical connection between thefoundation and the foundation section.

In other words, the foundation mass is poured into the foundation bednot only in the area around the foundation segment, but also into theinterior of the hollow foundation segment, in order that said foundationsegment is not exposed to lateral forces resulting from the foundationmass being poured into the outer area, which could lead in turn to thefoundation segment changing its position when the foundation mass isbeing poured. Due to the fact that foundation mass is also poured intothe interior of the foundation segment, the latter is stabilized in itsposition and cannot be tilted or changed in its position by foundationmass poured into the outer area.

It is preferred that the vertical adjustment for the support poles beprovided on the lower end of the support poles facing the subbase. Thiscould be accomplished with an adjuster nut, for example. Preferably, thesupport pole itself has an internal threaded rod for performing suchvertical adjustment.

In one advantageous configuration of the method according to theinvention, there is a means for measuring the current verticaladjustment of the separate supporting brackets. This is preferablyachieved with optical measurement means, such as a measurement meansthat transmits a focused laser beam in a horizontal direction, withmatching sensors mounted on the supporting brackets. Said sensorsgenerate a sensor signal containing information about the current heightof the supporting bracket, thus permitting vertical adjustment so thatthe foundation segment is horizontally aligned. Furthermore, controlleddrive means for vertical adjustment of the supporting brackets can alsobe provided that automatically adjust the height of the supportingbrackets in response to the sensor signals that are detected.

Support poles according to the invention and of the kind preferably usedin the inventive method are defined in claims 12 to 18. A foundationsegment according to the invention and with the described features isdefined in claims 19 and 20. The invention also relates to a windturbine with a tower comprising a plurality of segments, the lowermostsegment being a foundation segment of the kind described and thefoundation of the tower being made by the method described.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention shall now be explained in greater detail with reference tothe drawings. These show:

FIG. 1 shows a wind turbine according to the invention, with a towercomprised of a plurality of segments;

FIG. 2 shows a first configuration of a foundation segment according tothe invention;

FIG. 3 shows a section of the inventive foundation segment in FIG. 2,with a support pole;

FIG. 4 showsa second configuration of a foundation segment according tothe invention;

FIG. 5 shows a cross-section of the foundation segment in FIG. 4, with asupport pole;

FIG. 6 shows a section of the inventive foundation segment in FIG. 5;

FIG. 7 shows a further section of the inventive foundation segment inFIG. 5;

FIG. 8 shows a supporting bracket of a support pole shown in FIG. 5;

FIG. 9 shows a front view of a further configuration of a support poleaccording to the invention;

FIG. 10 shows a side elevation view of the support pole in FIG. 9;

FIG. 11 shows a side elevation view of a further configuration of aninventive support pole, with a drive means;

FIG. 12 shows a front view of a further configuration of an inventivesupport pole, with a sensor for vertical adjustment;

FIG. 13 shows a plan view of a foundation segment according to theinvention, illustrating the generation of sensor signals for verticaladjustment; and

FIG. 14 shows a block diagram of a vertical adjustment sensor asprovided in one configuration of the support poles.

DETAILED DESCRIPTION OF THE INVENTION

The wind turbine 1 shown schematically in FIG. 1 has a tower 2comprising a plurality of segments 3, wherein the lowermost segment 4,the so-called foundation segment, is embedded in a foundation 5. Anacelle 6 is rotatably mounted at the top of the tower 2, and a rotor 7with a plurality of blades 8 is attached to said nacelle. Disposedinside nacelle 6 is an electrical generator that is made to rotate bythe wind forces acting on the rotor blades 8, thus generating electricalenergy.

The segments 3, including foundation segment 4 of tower 2, arepreferably steel elements, but generally can also be prestressedconcrete elements into which prestressing steel elements or braces, forexample, are cast. Foundation segment 4 is cast into a foundation block9 that preferably consists of concrete. Said foundation block 9 mayextend above the surrounding ground 10 or end level with the ground, butin any case covers the lower rim of the foundation segment 4 as well asthe support poles 11 attached to the underside of said foundationsegment 4. By means of said support poles 11, the foundation segment ispropped on a subbase 12, which is a cement or concrete bed made as leveland horizontal as possible and cast in the foundation bed beforefoundation segment 4 with support poles 11 is erected.

FIG. 2 shows the main element of foundation 5 prior to casting of thefoundation mass to form foundation block 9. To make the foundation, afoundation bed 13 is excavated from the ground 10. A subbase 12, theupper surface of which should be as level and horizontal as possible, isthen made on the floor of the foundation bed. Before foundation segment4 is placed on subbase 12, three support poles 11 are first attachedfixedly to the underside 41 of foundation segment 4. In order to achievemaximum uniformity of load distribution and optimal support of thefoundation segment on the support poles 11, said support poles each havea support plate 110 fixedly attached as a support to the upper endfacing the underside of foundation segment 4, by means of which thesupport poles 11 are attached, preferably tightly bolted, to a flange 42of the foundation segment. Support poles 11 are also uniformly spacedapart or arranged at predefined positions around the circumference ofthe cylindrical foundation segment 4. Before foundation segment 4 is setdown, points of support 14 are marked on subbase 12 and reinforced withbase plates in order to prevent the support poles 11 from penetratingthe subbase 12. Once foundation segment 4 has been set down on baseplates 14, it can be adjusted in height by means of support poles 11 sothat foundation segment 4 is as horizontal as possible. For thispurpose, support poles 11 have vertical adjustment means 111 that may beconfigured as an internal threaded rod with an adjuster nut.

After foundation segment 4 has been vertically adjusted, it is thenreinforced. This is done by braiding reinforcement wires through theholes in the row of holes 43 provided in the side walls of foundationsegment 4. In a final step, foundation bed 13 is completely filled withfoundation mass, preferably concrete. The foundation mass is poured notonly into the outer cavity of foundation segment 4 but also into theinterior space 44 of foundation segment 4, to ensure that the positionof the foundation segment is not changed, for example as a result oflateral forces exerted externally on the foundation segment by thefoundation mass when it is being poured. Owing to the fact thatfoundation reinforcement wires are fed through the holes in the row ofholes 43, tensile forces can also be safely conducted from the towerinto the foundation. Once foundation segment 4 has been firmly encast,the remainder of the tower can be assembled.

FIG. 3 shows a more detailed section of foundation segment 4 with asupport pole 11. It can be seen how support pole 11 is bolted to flange42 of foundation segment 4 by means of support plate 110 fixedlyattached to support pole 11. In at least the lower portion of supportpole 11, an internal threaded rod 114 is provided to which an adjusternut 112 is fitted in order to adjust the height, i.e., to change thelength of support pole 11. Adjuster nut 112 supports itself against theouter jacket of support pole 11, thus permitting lengthwise adjustmentof the threaded rod 114. The fixed nut 113 enables the threaded pole 114to be securely held such that it cannot turn at the same time as nut 112is turned.

FIG. 4 shows an alternative configuration of a foundation segmentaccording to the invention, in which other support poles 21 are used.What is shown is again foundation segment 4 supported on three supportpoles 21. Between the subbase 12 and the support poles 21, supportplates 14 for distributing the weight are provided in order to preventthe support poles 21 from penetrating the subbase 12.

In this particular configuration, the support poles 21 extend inside theinterior 44 of foundation segment 4 as far as its upper rim, as can beclearly seen in FIG. 5. The latter Figure shows a foundation segment 4with a single support pole 21 in cross-section. The support pole 21 iscomprised of several parts and has a supporting bracket 210, a middlesection 211 and an end member 212 with a base plate 213. Supporting leg210 is for attaching support pole 21 to the upper flange 45 offoundation segment 4. The middle section 211 is attached to thesupporting bracket 210, on the one hand, and also to end member 212, forexample by screwing it into end member 212 by means of a threadedportion in a transition section 214. Transition section 214 ispositioned above the row of holes 43 at a height where it is not coveredwith foundation mass after the foundation bed has been completelyfilled. Only the end member 212 of each support pole 21 is covered bythe foundation mass, whereas the middle section 211 and the supportingbracket 210 can each be re-used.

To provide better support for the foundation segment, support pole 21 ispassed through an eye 46 attached to the lower flange 42, as can seen indetail in FIG. 6.

FIG. 7 shows the upper portion of the support pole, i.e., part of themiddle section 211 and the supporting bracket 210. Supporting leg 210comprises several parts for attaching the support pole 21 to the upperflange 45 of foundation segment 4 and for adjusting or aligning theheight of the foundation segment when making the foundation. Plates 22,23 are located above and below the circumferential flange 45. The lowerplate 22 partially conceals a screw 27 that grips through the pattern ofholes 47 in the upper flange 45 and attaches the upper plate 23 of thesupporting bracket 210 to foundation segment 4. Inside foundationsegment 4, there are also two threaded poles 24 running between the twoplates 22, 23, said threaded poles permitting the position of the upperplate 23 to be adjusted relative to the rest of supporting bracket 210by means of nuts 25. A rod 26 attached to the upper plate 23 slidesinside the middle section 211, the latter serving as an outer pipe.Since foundation segment 4 is connected to upper plate 23, any change inthe position of upper plate 23 also causes the entire foundation segment4 to move relative to the subbase 12.

The upper plate 23 can be adjusted, by raising the foundation segment 4with suitable lifting equipment, for example, such as a crane. Nuts 25visible underneath the upper plate 23 (see also FIG. 8) can thus beadjusted until the desired position is reached. After such adjustment,foundation segment 4 can be lowered again until it is located in thedesired position. This makes it easy to vertically adjust or align thefoundation segment when the foundation is being constructed.

Another configuration of a support pole according to the invention isshown in a front view and a side elevation view in FIGS. 9 and 10,respectively. The end member 212, as shown in FIG. 5, is again passedthrough an eye on the lower rim of the foundation section. What is alsounchanged is that said end member is encast inside the foundation and isnot used again. The foundation is filled to a height indicated in saidFigures by line 217. In order to prevent moisture penetration, caps 215are provided that can be used, after removing the re-usable part of thesupport pole from the end member,212, to cover what are then open ends.

The upper portion of said support pole is also largely identical to thesupport pole previously described. There are two plates 22, 23 betweenwhich threaded poles 24 with nuts are disposed. In the front view inFIG. 9, two threaded poles 24 with nuts 25 can be seen; in the sideelevation view in FIG. 10, these are aligned one behind the other, whichis why only one threaded pole 24 with nut 25 can be identified. In FIG.10, a part of the upper plate 23 is broken open to show a through hole28. Plate 23 and hence the support pole can be connected to the upperflange of the foundation segment through said through hole 28.

To simplify vertical adjustment and further reduce the proportion ofmanual work, an arrangement comprising a telescopic cylinder 29 and atelescopic pole 26 is provided between the two plates 22, 23. Saidcylinder can be operated pneumatically or hydraulically, for example,and thus permit easy adjustment of the foundation section joined to thesupport pole. In this embodiment, threaded pole 24 and nut 25 serve, onthe one hand, to fixate the position that is initially set by hydraulicor pneumatic means, and on the other hand as an “emergency actuation”means for manually adjusting the foundation section in the event thatthe hydraulic or pneumatic system fails.

In FIG. 11, to provide a better overview, only the upper portion of asupport pole according to the invention is shown as far as thetransition to the end member 212. Said Figure also includes part offoundation section 4. The latter is joined to the upper plate 23. Rod 26can be in the form of a threaded rod that is rotatably mounted at itslower end and turned by a drive means 216 such that plate 23 can bevertically moved with a matching thread, depending on the direction ofrotation. This also changes the vertical position of foundation segment4 attached to the upper plate. The control systems for drive means suchas electric motors, as well as the control systems for the cylinders 26,29 shown in FIGS. 9 and 10 are well known, so they are not described herin further detail.

FIG. 12 shows a further embodiment of a support pole according to theinvention that permits the supporting bracket to move automatically intoa pre-definable position. The same Figure shows only the upper potion ofthe support pole according to the invention, again for a betteroverview. This structure is substantially the same as that of thevariant shown in FIGS. 9 and 10.

However, a sensor 30 is provided here in addition to the elements shownin FIGS. 9 and 10. Said sensor comprises a plurality of light-sensitiveelements 32 arranged in a housing 31, such as phototransistors,photoresistors or the like. Filters may also be provided, or thelight-sensitive elements 32 can be configured in such a way that theyrespond only to a predefined spectral range in order to minimize orcompletely eliminate the influence of stray light and daylight.

Thus, if a light source is provided in a predefined horizontal position,the light from said light source will strike the light-sensitiveelements 32 regardless of the alignment of said light source, on the onehand, and the adjusted position of the supporting bracket, on the otherhand. If said light is now sufficiently focused, only some of thelight-sensitive elements 32 are struck by the light. This makes itpossible to derive the vertically adjusted position of the respectivesupporting bracket relative to the light source. Thus, if sensor 30 isin a clearly defined position and the light source is also in a clearlydefined position, it is possible to derive a correcting variable, forexample from the deviation of the incident beam of light from a from apredefined position in sensor 30, e.g., its centre, that can be used tochange the vertical adjustment of the supporting bracket. In this way,it is possible for the foundation section to be automatically adjusted.

An example of this arrangement is shown in FIG. 13. The latter shows aplan view of a foundation section 4, on the inner side of which threesupport poles according to the invention are arranged at 120° to eachother. The important aspect of this arrangement is that the alignment ofthis foundation section is oriented to the upper flange, because saidflange must be exactly horizontal in its alignment, whereas thealignment of the lower flange of the foundation section is irrelevantfor easily understandable reasons. A light source 35 is installed in thecentre of foundation section 4, for example on a tripod 36, and alignedso that it is perfectly horizontal. Said light source 35 can transmit alaser beam 37, for example, the light from which is still sufficientlybundled, even at a considerable distance, and which moves in a 360°circle inside the foundation, section.

Each of the three supporting brackets is shown with its upper plate 23,which is fixedly attached to the foundation section 4. Also shown arethe threaded rods 24, the drive means 216 and the sensor 30. If laserbeam 37 now rotates with perfect horizontal alignment, a signal isgenerated at each sensor 30, said signal providing an indication as towhether the supporting bracket at that point is in the desired position,or must be adjusted by actuating the drive means 216, or manuallyadjusted.

In practice, vertical adjustment of the supporting brackets ispreferably performed in such a way that one of the supporting bracketsis first brought into a predefined position, that this supportingbracket is then left unchanged, and the alignment of foundation section4 is then performed on the two other supporting brackets.

Sensor 30 can, of course, exercise a direct influence on drive means 216with its output signal. On the other hand, a centralized control systemcan be provided that analyses the sensor signal and outputscorresponding signals for actuating the associated drive means 216.

FIG. 14 shows, in simplified form, an example of a sensor 30. In saidsensor 30, light-sensitive sensor elements 32 are arranged beside and/orabove each other. By way of illustration, these sensor elements areshown here as phototransistors. The external circuitry of thetransistors has been left out for the sake of a better overview, but arecommon knowledge to the person skilled in the art. The collectors ofthese phototransistors 32 are connected in parallel to the power supplyat a connector 51.

Depending on the position of the transistor in this sensor, the emittersof the transistors are connected to gates, or form a signal output. Theemitters of the upper nine transistors shown in this Figure areconnected to the input terminals of an OR-gate 50. The output from thisgate 50 is available as an output signal 52. The emitters of the lowernine phototransistors shown in this figure are similarly connected toinput terminals of an OR-gate, the output 53 from which is similarlyavailable as an output signal. The output of the middle phototransistoris directly available as output signal 54. All outputs may also beconducted through amplifier stages, of course.

If sensor 30 is installed in such a way that the desired horizontalposition is reached when the middle transistor is illuminated, it iseasy to conclude from this that, whenever light shine on one of thephototransistors above this middle transistor, the sensor and hence thesupporting bracket are positioned too low. Gate 50 causes a signal toappear at output 52 that triggers an upward adjustment of the supportingbracket and hence of the sensor. If the light falls on a phototransistorbelow the middle phototransistor, it can be concluded from this that thesupporting bracket must be adjusted to a lower position. As soon as themiddle phototransistor output a signal at terminal 54, this can be usedas a “Stop” signal for terminating adjustment of the supporting bracket.

Since the absolute height, e.g., above mean sea level, is not strictlydefined for the upper flange of the foundation section, there is analternative procedure for aligning the foundation section that can alsobe considered. In this procedure, one of the supporting brackets isfirst set to a desired height. The rotating beam of light will thereforestrike one of the light-sensitive elements 32. This sensor outputs asensor signal that permits the light-sensitive element 32 struck by therotating light beam to be inferred, and that therefore represents theadjusted height of the supporting bracket. Such a signal can be ananalog signal, or a digital signal, e.g., a binary-coded signal. Thissignal can be fed to a central controller, for example. When the twosupporting brackets still to be adjusted are moved until each of theassigned sensors outputs the same signal to the central controller,i.e., until the same sensor element is struck by the light beam, thefoundation section has again been horizontally aligned.

Other configurations of the sensors and a different way of adjusting thesupporting brackets are also possible, of course. For example, oneconfiguration provides for a reflecting element that reflects anincident beam of light to be disposed at the same vertical position oneach supporting bracket. Not only the light source but also a matchingreceiver is then disposed at the centre of the foundation section. Onlywhen the light beam hits the reflector element is a reflected beam oflight received by the receiver, thus signaling the correct verticalposition.

All of the above U.S. patents, U.S. patent application publications,U.S. patent applications, foreign patents, foreign patent applicationsand non-patent publications referred to in this specification and/orlisted in the Application Data Sheet, are incorporated herein byreference, in their entirety.

The invention is not limited to use in wind turbines, but canessentially be applied in any kind of structure comprising at least twosegments in order to make a stable foundation. The number, arrangementand specific configuration of the elements shown in the Figures, inparticular the support poles, can be varied.

From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. A method for building a foundation for a structure comprising aplurality of segments, in particular for a tower of a wind turbine, withthe following steps: a) excavating a foundation bed, b) building astable, substantially level and horizontal subbase (in a foundation bed,c) setting down a foundation segment of the structure on the subbase,wherein at least three vertically adjustable support poles are fixedlyattached to said foundation segment by means of a supporting bracketmounted at the end of the support poles in such a way that only thesupport poles are set down onto predetermined points of support on thesubbase, d) producing a reinforcement on the subbase, e) casting theremainder of the foundation bed with foundation mass, in particularconcrete, to a level above the bottom rim of the foundation segment. 2.The method according to claim 1, characterized in that the support polesare each attached by means of support plates to a flange on theunderside of the foundation segment.
 3. The method according to claim 1,characterized in that the support poles, each having an internalthreaded pole, are vertically adjusted by means of a vertical adjustmentdevice disposed at the lower end of the support poles facing thesubbase.
 4. The method according to claim 1, characterized in that thesupport poles are each mounted on a flange at the upper rim of thefoundation segment.
 5. The method according to claim 4, characterized inthat the support poles are passed through eyes on the lower rim of thefoundation segment and extend into the foundation segment.
 6. The methodaccording to claim 1, characterized in that the remaining foundation bedis filled with foundation mass by firstly casting in foundation massuntil approximately the lower rim of the foundation segment is reached,after which any vertical alignment of the foundation segment isperformed and that the remaining foundation bed is subsequently filledwith foundation mass.
 7. The method according to claim 1, characterizedin that the points of support on the subbase are mechanicallyreinforced.
 8. The method according to claim 1, characterized in thatreinforcement is braided through the holes provided in the side walls ofthe foundation segment, and that the remainder of the foundation bed isfilled mit foundation mass to such a height that the holes are coveredover by foundation mass.
 9. The method according to claim 1,characterized in that the currently adjusted height of the separatesupporting brackets is measured by suitable measurement means, inparticular optical measurement means, in order to adjust the height ofsaid supporting brackets.
 10. The method according to claim 9,characterized in that, for the purpose of adjusting the height of thesupporting brackets a height measurement signal, in particular a bundledlight beam is transmitted in a horizontal direction from a transmitterdisposed inside the foundation segment, in particular from a lightsource, to the supporting brackets fitted with a corresponding sensor,in particular an optical sensor, that a sensor signal is generated bythe sensors, each signal containing information about the adjustedheight of the respective supporting bracket, and that the associatedsupporting bracket is vertically adjusted in response to the sensorsignal generated.
 11. The method according to claim 10, characterized inthat the supporting brackets are vertically adjusted by means of acontrolled drive means, wherein the sensor signals generated by thesensors analyzed in order to control said drive means.
 12. A supportpole, in particular for use in the method according to claim1,_characterized by an outer pipe, a threaded pole disposed therein anda supporting bracket, in particular in the form of a support plate, atone end of said outer pipe.
 13. The support pole according to claim12,_characterized by a nut screwed onto the end of the threaded polefacing away from the supporting bracket and supporting itself againstthe outer pipe.
 14. A support pole, in particular for use in the methodaccording to claim 1,_characterized by an outer pipe and a supportingbracket at one end of the support pole, wherein the supporting brackethas a pole displaceable inside the outer pipe, a first plate mounted onthe outer pipe and a second plate mounted on the pole, said plates beingconnected by means of at least one threaded pole for changing the gapbetween the two plates, and wherein the second plate is configured forfixed attachment to an element to be supported.
 15. The support poleaccording to claim 12, characterized by a base plate at the opposite endsupport pole from the supporting bracket.
 16. The support pole accordingto claim 12,_characterized by drive means, in particular hydraulic orpneumatic drive means, for vertical adjustment of the supportingbrackets.
 17. The support pole according to claim 12,_characterized by asensor*, in particular an optical sensor, disposed on the supportingbracket for receiving a signal from the sensor and for generating asensor signal containing information about the adjusted height of thesupporting bracket.
 18. The support pole according to claim17,_characterized in that the sensor has a plurality of sensor elementsarranged along the longitudinal direction of the support pole.
 19. Afoundation segment for a structure comprising a plurality of segments,in particular for a wind turbine tower, characterized in that leastthree vertically adjustable support poles are fixedly attached to thefoundation segment by means of a support plate mounted at the end of thesupport poles for setting the foundation segment down on supportingpoints of a subbase in a foundation bed.
 20. The foundation segmentaccording to claim 19,_characterized in that holes are provided in theside walls of the foundation segment, in particular a circumferentialrow of holes, through which reinforcement steel is passed in order toestablish a mechanical connection between the reinforcement and thefoundation segment.
 21. A wind turbine with a tower comprised of aplurality of segments, wherein the lowermost segment is a foundationsegment according to claim
 19. 22. The wind turbine with a towercomprising a plurality of segments, wherein the foundation of the toweris manufactured in accordance with claim 1.